An issue has been discovered in GitLab CE/EE affecting all versions starting from 13.2. When querying the repository branches through API, GitLab was ignoring a query parameter and returning a considerable amount of results.
https://gitlab.com/gitlab-org/gitlab/-/issues/322500
https://gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-22210.json